Permanently sterilized dental material



Unites K t PERMANENTLY STERILIZED DENTAL MATERIAL Adolf Knappwost,Neuhausen, near Urach, Germany, assignor to Vivadent Corporation,Boston, Mass, a corporation of Massachusetts No Drawing. ApplicationOctober 6, 1953, Serial No. 384,509

Claims priority, application Germany October 15, 1952 6 Claims. (Cl.106-65) The present invention relates to dental materials which arerendered permanently sterile by the inclusion of a disinfecting agentwhich inhibits the growth of acid forming bacteria in the oral cavity.Such dental materials include cements and other materials such as thosehaving a plastic base.

Among the presently known disinfecting, sterilizing, or prophylacticmaterials, the most satisfactory for dental use are salts of copper.Cuprioxide, because of its dark brown color, is unsuited for use in theoral cavity, except in the molar region. Cuproiodide is insufiicientlysoluble for effective prevention of bacterial growth. It inhibits thegrowth of certain bacteria, but not the action of their enzymes whichcatalyze the formation of destructive acids. As the salt of a strongacid, cuproiodide shows only a negligible increase in solubility inslightly acid solutions, thus impairing its elfeetiveness as aninhibiting agent.

Accordingly, it is among the objects of the present invention to producea permanently sterile dental material sufliciently light in color topermit its use in all portions of the oral cavity.

A further object of the invention is the provision of an acid-sensitivedental material of this character in which copper ions are released inthe presence of relatively low hydrogen ion concentrations in order thatthe inhibiting action of the sterilizing agent may become effective assoon as the destructive action of the acid forming bacteria commences.

Still another object of the invention is the provision of a copper saltas an inhibiting agent, the copper salt being of such character as toresist complete solution when mixed to form a cement using a cementliquid containing phosphoric acid.

Other and further objects will become apparent upon reading thefollowing specification.

In accordance with the present invention, oxalates and basic oxalates ofcopper are used to inhibit the growth of acid forming bacteria. Theseoxalates are the salts of an acid which is only moderately strong. Theyexhibit increasing solubility with increasing hydrogen ionconcentration, but are not entirely dissolved when mixed to form acement using a cement liquid which contains phosphoric acid. In the caseof a salt of a weak acid, such as copper silicate or copper borate, thecopper salt is substantially completely dissolved by the phosphoric acidof the cement liquid, and after solidification of the cement, the copperis present in the form of cupriand cupro-phosphate.

Cuprioxalate is of a light green-blue color and cuprooxalate is evenlighter in color. These salts have no unsightly discoloring effect whenincluded in a dental cement. The use of up to 10% by weight of suchsalts when added to a cement powder does not produce any ofiensivestain. Moreover, cuprioxalate and cuprooxalate may also be used asadditives to non-cementitious dental materials, such as plastics.

REFERENCE:

2,798,816 Patented July 9, 1957 Also taking into consideration, the factthat any material inhibitive of the growth of acid producing bacteriamust not only inhibit bacterial growth in the dental structure to whichit is applied, but must operate to provide effective prophylaxis of thesurrounding tooth structure, in order to avoid the development ofdangerous secondary caries. For this reason, the oxalates of copperwhich form the subject matter of the present invention are particularlyvaluable when included as a component of any substance intended for usein the oral cavity.

The basic oxalates of copper, whether monoor divalent, are suitable foruse in the same manner as the normal oxalates. Dental materials, whetherused for filling, adhesive or other purposes may be made inherentlypermanently inhibitive to the growth of destructive acid formingbacteria by the inclusion in their composition of up to 10% by weight ofeither a normal oxalate of copper or a basic oxalate thereof. Thefollowing examples are given by way of illustra tion.

Example 1 1 kg. dry zinc phosphate cement powder and 50 g. drycuprioxalate are ground together in a ball mill until a mixture ofhomogeneous appearance is obtained. One gram of this mixture is mixed ona glass slab with 0.3 g. of the usual cement liquid using a plasticspatula. The resulting cement porridge is used in the conventionalmanner for the fixation of crowns, bridges, etc.

Example 2 1 kg. of dry zinc phosphate cement powder is combined as inExample 1, using 50 g. of dry cuprooxalate instead of cuprioxalate.

Example 3 1 kg. of dry zinc phosphate cement powder is combined as inExample 1, using 50 g. of dry basic cuprioxalate.

Example 4 1 kg. of dry zincphosphate cement powder is combined as inExample 1, usingjO g. of dry basic cuprooxalate. Having thus describedmy invention, what is claimed 1. A permanently bactericidal dentalcement consisting essentially ofa base material and a bactericidalamount up to 10% by weight of a copper salt selected from the groupconsisting of cuprioxalate, cuprooxalate and the basic oxalates ofcopper.

2. A substance as in claim 1, wherein said oxalate is basiccuprioxalate.

3. A substance as in claim 1, normal cuprioxalate.

4. A substance as in claim 1, basic cuprooxalate.

5. A substance as in claim 1, normal cuprooxalate.

6. The process for destroying acid-forming bacteria in the oral cavity,which comprises applying to the oral cavity a cementitious compositionin which a copper oxalate is present in a bactericidal amount up to 10%by weight.

wherein said oxalate is wherein said oxalate is wherein said oxalate isReferences Cited in the file of this patent UNITED STATES PATENTS1,226,232 Mahan May 15, 1917 1,886,982 Simon Nov. 8, 1932 FOREIGNPATENTS 134,156 Australia Sept. 6, 1947 OTHER REFERENCES Gregory: Usesand Applications of Chemicals and Related Materials, vol. II (1944),page 87.

1.A PERMANENTLY BACTERICIDAL DENTAL CEMENT CONSISTING ESSENTIALLY OF ABASE MATERIAL AND A BACTERICIDAL AMOUNT UP TO 10% BY WEIGHT OF A COPPERSALT SELECTED FROM THE GROUP CONSISTING OF CUPRIOXALATE, CUPROOXALATEAND THE BASSIC OXALATES OF COPPER.